Hello, please can you all help me with this. I want to install IP phones (VOIP) for a client. for voice, they ran cat 3 cables (for proprietary pbx). please is there a way i can convert those cat3 cables to cat 5 without recabling? (the cables are buried underground). Thanks all.
I'd look at validating 100% the specs of the voip phones, or looking for phones (maybe a different brand?) that work on cat 3. If something requires 8 wires, and you have 4 wires... well... you're short 4 wires. Unless you can somehow use 2 runs per connection to get 8 wires.
See this discussion for example (discusses some mitel phones that can run over cat 3 as long as you don't use the 2nd port on the phone for data)
there is no way to convert cat3 cable to cat5 . . if there is enough room though, you could tie some cat 5 cable to the ends of the cat 3 cable . . then at the other end pull the cat 3 out which will pull the cat5 into its place.
thanks Grumpy9117 and gtvr, but the cat 3 cables have been run using 2 pairs. We want to avoid recabling at all costs. we know that VOIP uses 4 pairs so pls is there perhaps a converter?
Hmm, I just converted my house to VOIP running on Cat5e, and for one VOIP adapter it only uses one pair out of the 4 available (blue + blue-white twisted pair). If I wanted to run another adapter for a second line, I'd use the next available pair, etc., but with cloned lines I don't really need another adapter.
See THIS link for more information, plus they seem to think Cat3 is fine for VOIP. At least they don't recommend replacing it as they do regular 4-wire telephone cabling (in which the wires are not twisted pairs) because of crosstalk and other interference.
Indeed as already mentioned there is no way of converting Cat3 into Cat5 or Cat5e.
If fact, Cat3 is totally different than Cat5. HOWEVER, you may get similar speed using Cat3s as Cat5 under 100MB. Over it is almost impossible.
Also, you may be able to use ONLY 2 pairs in order to get it running. Normally, you may use wires 1,2,3 and 6 as regular RJ45 jack ethernet. Wires 4 and 5 (the Internal middle pair) is widely used as Phone line. Wire pair 7 and 8 are not used at all, SO, IN OTHER WORDS, you can do this:
Cat3 - use multiple pairs (2) in order to get it running as Ethernet;
Cat5 - use wires 1,2,3 and 6 as regular one and you can use inside the same cable wires 4,5,7 and 8 as 2nd Ethernet. NO PROBLEM. Beware that this is a workaround avoiding recabling. Unless you really need speeds over 100MB - which I sincerely doubt - you can do this.
Regarding the VoIP adapter, RJ11 is similar to RJ45. RJ11 has 4 cables, RJ45 has 8. Phisically speaking, the RJ11 male FITS into a RJ45 female normally, which is worldwide used by VoIP or regular phones. If you pick a regular RJ11, the internal pair is line one, both outside wires are line two.
Wish you all the best. Hope you don´t need to re-wire. Is there any possibility to use 802.11n? This may be also a solution. The max tested speed on most n Networks is around 8MB, which should be more than enough for your VoIP. VoIP normally uses something around 20 kB.